I. Field of the Invention
This invention relates to corona generators and more particularly to an electrically driven ozone generator having a solid state power supply for providing a high voltage, high frequency potential to the corona gap of each cell in a plural cell ozonator. Such ozone generators have many commerical and scientific uses, one of which, for example, is the supply of ozone to an air pollutant measuring instrument of the chemiluminescent monitoring type such as is disclosed in the copending application of John D. Von Bargen and Khalid U. Siddiqui filed on Apr. 21, 1975, entitled "Monitor for Detection of Chemiluminescent Reactions" and assigned to the same assignee as is the present application.
II. Description of the Prior Art
The basic physical principles of obtaining ozone by passing pure oxygen or other gasses containing oxygen through a corona discharge maintained across the gap between two electrodes have been known for many years. The basic prior art is, for example, illustrated in U.S. Pat. No. 3,455,803 issued to F. A. Miller on July 15, 1969 and by the prior art cited therein. Over the years, efforts have been made to refine these generators and the power supplies forming an integral part of their operating circuitry. These efforts have been particularly directed at increasing efficiency and reducing both the cost of operation and the cost of manufacture as well as increasing the output of ozone per unit of power consumed. Many factors have contributed to setting the prior art limits on efficiency. These factors and the efforts made to increase efficiency in the light thereof are discussed, for example, in U.S. Pat. No. 3,496,092 issued on Feb. 17, 1970 to J. C. Frazer; in U.S. Pat. No. 3,784,838 issued on Jan. 8, 1974 to Frank E. Lowther; and in U.S. Pat. No. 3,800,210 issued on Mar. 26, 1974 to George Caussin. The commercially available ozone generators, however, remain relatively bulky and inefficient relying either on iron core step up transformers or choke coils in the circuitry for supplying the high voltage potential to the ozonator electrodes.
It is an object of the present invention to provide an ozone generator of improved efficiency over the prior art to thereby minimize the electrical power consumed per pound of ozone produced.
It is a more particular object of the invention to provide such apparatus which eliminates the need for iron core transformers or choke coils by utilizing a capacitatively coupled auto-transformer of the automotive ignition coil type to supply a very high voltage, high frequency potential to the ozonator electrodes which form a parallel tuned circuit with its output.
It is another specific object of the invention to provide an ozone generator comprising a plurality of such ozonator cell groups, each of which has its individual high voltage supply all of which are connected in parallel across the output of a single power rectifier state and are fed through a single current limiting impedance in series with all of the parallel connected outputs to thereby minimize the power loss in the voltage drop across the limiting impedance.